Syphilis
Syphilis is a sexually transmitted disease caused by the bacterium Treponema pallidum.
Syphilis is highly contagious during the primary and secondary stages: a single sexual encounter with a person who has syphilis results in infection about one third of the time. The bacterium enters the body through mucous membranes, such as those in the vagina or mouth, or through the skin. Within hours, the bacterium reaches nearby lymph nodes, then spreads throughout the body by way of the bloodstream. Syphilis can infect a fetus during pregnancy (see Section 23, Chapter 264), causing birth defects and other problems.
The annual number of people with newly diagnosed symptomatic syphilis last peaked in 1990, with 50,000 cases in the United States. Since then--largely because of focused public health measures--numbers have been dropping; 35,600 total and slightly more than 6,000 symptomatic cases were reported in 1999. Thus, most cases are detected in people without symptoms.
Symptoms
Symptoms of syphilis usually begin 3 to 4 weeks after infection, although they may start as early as 1 week or as late as 13 weeks after infection. Syphilis progresses through several stages (primary, secondary, latent, and tertiary) if not treated. Infection can persist for many years and may cause heart damage, brain damage, and death.
In the primary stage, a painless sore or ulcer (chancre) appears at the infection site--typically the penis, vulva, or vagina. The chancre may also appear on the anus, rectum, lips, tongue, throat, cervix, fingers, or, rarely, other parts of the body. Usually, a person has only one chancre, but occasionally several develop.
The chancre begins as a small red raised area, which soon turns into a painless open sore. The chancre does not bleed and is hard to the touch. Nearby lymph nodes usually swell and are also painless. About half of infected women and one third of infected men are unaware of it. Others ignore the chancre because it causes few symptoms. The chancre usually heals in 3 to 12 weeks, after which the person appears to be completely healthy.
The secondary stage usually begins with a skin rash, which typically appears 6 to 12 weeks after infection. About 25% of infected people still have a healing chancre at this time. The rash usually does not itch or hurt and can have many different appearances. Unlike rashes from most other diseases, the rash of secondary syphilis commonly appears on the palms or soles. The skin rash may be short-lived or may last for months. Even if a person is not treated, the rash eventually clears up. New rashes, however, may appear weeks or months later.
Secondary-stage syphilis is a generalized disease that can cause fever, fatigue, loss of appetite, and weight loss. Mouth sores develop in more than 80% of people. About 50% have enlarged lymph nodes throughout the body, and about 10% develop inflammation of the eyes. The eye inflammation usually causes no symptoms, although occasionally the optic nerve swells, which may cause some blurring of vision. About 10% of people have inflamed bones and joints that ache. Jaundice may result from inflammation of the liver. A small number of people develop acute syphilitic meningitis, which causes headaches, neck stiffness, and sometimes deafness.
Raised areas (condylomata lata) may develop where the skin adjoins mucous membrane (for example, at the inner edges of the lips and vulva) and in moist areas of the skin. These extremely infectious areas may flatten and turn a dull pink or gray. The hair often falls out in patches, leaving a moth-eaten appearance.
After the person has recovered from the secondary stage, the disease enters a latent stage, in which the infection persists but no symptoms occur. This stage may last for years to decades--or for the rest of the person's life. Syphilis is generally not contagious in the latent stage.
During the tertiary (third) stage, syphilis is also not contagious but produces symptoms that range from mild to devastating. Three main types of tertiary syphilis may occur: benign tertiary syphilis, cardiovascular syphilis, and neurosyphilis.
Benign tertiary syphilis is rare today. Lumps called gummas appear on the skin or in various organs. These lumps grow slowly, heal gradually, and leave scars. The lumps can develop almost anywhere in the body but are most common on the scalp, face, upper trunk, and leg (just below the knee). The bones may be affected, resulting in a deep, penetrating pain that is usually worse at night.
Cardiovascular syphilis usually appears 10 to 25 years after the initial infection. A person may develop an aneurysm (weakening and dilation) of the aorta (the main artery leaving the heart) or leakage of the aortic valve. These changes may lead to chest pain, heart failure, or death.
Neurosyphilis (syphilis of the nervous system) affects about 5% of all people with untreated syphilis, although it is rare in developed countries. It can cause many serious problems in the brain and spinal cord, interfering with thinking, walking, talking, and many other activities of daily life.
Neurosyphilis occurs in three forms: meningovascular, paretic (also called general paralysis of the insane), and tabetic (tabes dorsalis). Meningovascular neurosyphilis is a chronic form of meningitis that affects the brain and spinal cord. Paretic neurosyphilis usually does not start until the person is 40 or 50. It begins with gradual behavioral changes, such as deterioration in personal hygiene, mood swings, and progressive confusion. Tabetic neurosyphilis is a progressive disease of the spinal cord that begins gradually, typically with an intense, stabbing pain in the legs that comes and goes irregularly. Later, the person becomes unsteady while walking.
Diagnosis
A chancre or a typical rash on the palms and soles usually leads a doctor to suspect syphilis. A definitive diagnosis is based on the results of laboratory tests.
Two types of blood test are used. The first is a screening test, such as the Venereal Disease Research Laboratory (VDRL) or the rapid plasma reagin (RPR) test. Screening tests are inexpensive and easy to perform, but they may need to be repeated because the results can be falsely negative in the first few weeks of primary syphilis. Screening tests sometimes come back falsely positive because of diseases other than syphilis. Therefore, a positive screening test result usually must be confirmed with a second, specialized blood test that measures antibodies to syphilis bacteria. Screening test results become negative after successful treatment, but the second, confirmatory test stays positive indefinitely.
In the primary or secondary stages, syphilis may also be diagnosed by obtaining fluid from a skin or mouth sore and identifying the bacteria under a microscope. For neurosyphilis, a spinal tap (lumbar puncture) is needed to obtain spinal fluid for antibody testing. In the latent stage, syphilis is diagnosed only by antibody tests of the blood and spinal fluid. In the tertiary stage, syphilis is diagnosed from the symptoms and an antibody test.
Treatment and Prognosis
Because people with primary and secondary syphilis can pass the disease to others, they must avoid sexual contact or take careful precautions until they and their sex partners have completed treatment. With primary-stage syphilis, all sex partners for the previous 3 months are at risk of being infected. With secondary-stage syphilis, all sex partners for the previous year are at risk. Sex partners in these categories need to be screened with an antibody test performed on a blood sample. If the test is positive, they need to be treated. Some doctors simply treat all sex partners without waiting for test results.
Penicillin given by injection is the best antibiotic for all stages of syphilis. For primary-stage syphilis, a one-time treatment with penicillin is adequate, although some doctors repeat the dose in one week. For secondary-stage syphilis, the second dose is always given. Penicillin is also given for latent-stage syphilis and for all forms of tertiary-stage syphilis, although more frequent or longer treatment given intravenously may be needed. People who are allergic to penicillin may receive azithromycin once by mouth, ceftriaxone by injection daily for 10 days, or doxycycline by mouth for 14 days.
More than half of the people with syphilis in its early stages, especially those with secondary-stage syphilis, develop a reaction 2 to 12 hours after the first treatment. This reaction is called the Jarisch-Herxheimer reaction and is believed to result from the sudden death of millions of bacteria. Symptoms of the reaction include a feeling of overall illness, fever, headache, sweating, shaking chills, and temporary worsening of the syphilitic sores. Rarely, people with neurosyphilis may experience seizures or paralysis. The symptoms of this reaction are temporary and rarely cause permanent harm.
After treatment, the prognosis for primary-, secondary-, and latent-stage syphilis is excellent. The prognosis is poor for tertiary-stage syphilis of the brain or heart, because existing damage usually cannot be reversed. A person who has been cured of syphilis does not become immune to it and can acquire the infection again.
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